In recent weeks we have highlighted some areas in which the Psalms can enhance and improve our worship (specifically, in the areas of prayer and penitence). I suppose it goes without saying that the Psalms can be used even today as part of our worship in song (Eph. 5:19; Col. 3:16). But in this regard, a word of caution is in order. Some in churches of Christ who are pushing for the inclusion of instrumental music in our worship will run quickly to the Psalms and point out that since this great book enjoins worshiping God with instruments (cf. Psa. 150, et al.), that God must approve of it today.
As with all Old Testament passages, there are proper and improper uses of them (2 Tim. 2:15). One must respect that the Jewish people, for whom those Psalms were originally written, lived under a completely different religious system than do Christians today. Therefore, just because a particular expression of worship was enjoined under that old system does not mean that the same method of expressing worship pleases God today. If it did, then one would have to approve of all the other expressions of worship that were a part of that remedial system: animal sacrifice, Sabbath day worship, the burning of incense, facing Jerusalem in prayer, worshiping in the Jerusalem temple, the Levitical priesthood, and the keeping of the Passover – all of which are mentioned approvingly in the Psalms. If one is going to argue for the use of one of those expressions of worship (instrumental music) on the basis that it is approved in the Psalms, then there is no logical basis for disapproving of any and all of the others, which then begs the question, why did God remove that old covenant and replace it with the new (Heb. 8:6-13)?
Let us use the Psalms to help our worship today, but let us use them properly by respecting the covenant to which we are amenable. The Psalms, like all other Old Testament books, find their New Testament application in principle (cf. 1 Cor. 10:1-12), not in the specifics. Authorization for how we express worship to God today must come from the covenant under which we live, the New Testament. There is no New Testament authority for worshiping God in song accompanied by mechanical instruments